Ion chromatographic methods developed to separate either cationic, neutral, and anionic arsenic species or soluble and suspended arsenic species were successfully used in DORM-2 standard reference material and in water samples of environmental interest. The most effective separation of the analytes within 10 min was achieved with a nitric acid gradient elution using a strong anion-exchange stationary phase with additional capacity for hydrophobic interactions (IonPac AS7). The elemental-specific detection mode allows the sensitive determination of the arsenic species in the submicrogram per liter range. The calibration results were compared with those obtained by an alkaline water−methanol mixed eluent combined with a weak anion-exchange column (IonPac AS4A-SC). Differences in sensitivities were eclipsed by the low level of the baseline and the noise when using nitric acid. The gradient method was used to determine arsenic species in highly ferrous/ferric-contaminated leachates of lignite spoil. The companion elements underwent parallel screening to explain the interactions of arsenic species with the major elements.